High frequency diode encapsulations are presently known in the art for satisfactory operation at high frequencies. Other packages are available for operation at relatively high powers. Encapsulations for such applications however, thus far, do not combine in one package all of the characteristics required for both high frequency and high power operation.
In particular, high performance microwave diodes for use at X-band (9.2-12 GHz) and above, require the combination of hermeticity, thermal conductivity and mechanical strength coupled with very small dimensions. Certain packages known in the art provide hermeticity and mechanical strength but present large parasitic impedances and thermal resistances which make them unsuitable for high performance in the above-mentioned high frequency range. Other packages having more acceptable parasitic impedances and satisfactory thermal dissipation characteristics lack the other requirements of hermeticity and mechanical strength.
Solid state device packages exhibit both capacitance and inductance in use to some degree. The presence of unduly long conductive paths contributes to parasitic inductance. Typically, semiconductor diode housings utilizing relatively long cylindrical housings with end terminals have increased package inductance. On the other hand, short cylindrical housings are difficult to manufacture to precise dimensional tolerances. Glass and ceramics customarily used for such cylinders have relatively higher dielectric constants thus increasing the parasitic capacitance, particularly when the distance between the terminal ends of the package is decreased. Accordingly, there is need for a semiconductor diode package which meets and solves the foregoing encapsulation problems.